GLFW Manager - C++ wrapper with multi-threading

A GLFW C++ wrapper with additional OOP features.

Features

• C++11
• wrapping of GLFW window-related concepts
• multiple event handling
• handling of same event with multiple handlers
• binding of same handler to multiple windows
• multiple content drawing
• drawing of the same content in multiple windows
• grouping of windows
• multi-threaded drawing with groups
• window-to-window update notifications
• update notifications to whole groups
• automatic control of the loop

Compilation

Dependencies

There are two mandatory dependencies.

• GLFW, which must have already been installed on the system. See http://www.glfw.org for details. Alternatively, it is possible to get GLFW through package managers, such as apt-get (Linux) or MacPort/Homebrew (Mac OS).

• cmake, which is used to compile and install this library, greatly simplifying this tasks. See https://cmake.org for details. Alternatively, as before, it is possible to get cmake through package managers.

Building

Through cmake it is possible to compile and eventually import this library into another software. There are two ways to do that.

• install the shared library binaries somewhere on the system and then import it:

    mkdir glfwm_build
    cd glfwm_build
    cmake <path-to-glfwm>
    make
    make install
  

  Now glfwm is installed as a shared library depending on the value of CMAKE_INSTALL_PREFIX and can be linked to. Then in the cmake list file CMakeList.txt of another project just add:

    ...
    find_package(glfwm 3.3 REQUIRED)
    ...
    add_executable(myexe myexe.cpp)
    target_link_libraries(myexe glfwm)
  

  And that's all.

• include the library sources in a cmake list file CMakeList.txt of another project:

    ...
    add_subdirectory(<path-to-glfwm> ${${PROJECT_NAME}_BINARY_DIR}/glfwm)
    ...
    add_executable(myexe myexe.cpp)
    target_link_libraries(myexe glfwm)
  

  In this way, glfwm is compiled as a static library in the build tree of the myexe target.

Build options

There are some options that affect the compilation and/or installation:

• WITH_MULTITHREADING enables/disables multi-threading support. This allows windows to operate and be managed in separate threads.

• BUILD_SHARED_LIBS makes glfwm be built as a shared (if ON) or a static (if OFF) library.

• INSTALL_GLFWM makes glfwm be installed (if ON) or not (if OFF).

Default values mainly depends on the way it is built as described in the Building section above. BUILD_SHARED_LIBS and INSTALL_GLFWM are OFF when glfwm is included as a sub-directory, ON otherwise. WITH_MULTITHREADING is always ON.

It is possible to change these options either as argument to the cmake command, e.g. -DWITH_MULTITHREADING=OFF, or directly in the cmake list file of another project which includes glfwm:

...
option(WITH_MULTITHREADING "Build GLFWM with multithreading (i.e. thread-safe) or not." OFF)
add_subdirectory(<path-to-glfwm> ${${PROJECT_NAME}_BINARY_DIR}/glfwm)
...

Usage

The main purpose is to manage windows. So the main objects are Windows and a WindowManager which takes care of.

First of all, include the main header:

#include <GLFWM/glfwm.hpp>

Then initialize the library resources by calling

glfwm::WindowManager::init();

at the beginning of the program execution, e.g. in the main function before everything.

A Window can receive events and draw some content. For this purpose, special objects can bind to it.

Derive EventHandler and override the getHandledEventTypes() and handle() methods in order to react to events like cursor position changes and mouse button clicks. Then bind such objects to a Window s.t. events directed to it may handled:

class MyHandler : public glfwm::EventHandler {
    public:
    glfwm::EventBaseType getHandledEventTypes() const override
    {
        return static_cast<glfwm::EventBaseType>(glfwm::EventType::MOUSE_BUTTON);
    }

    bool handle(const glfwm::EventPointer &e) override
    {
        if (e->getEventType() == glfwm::EventType::MOUSE_BUTTON) {
            // make some action based on this event
            ...
            return true;
        }
        return false;
    }
};

Derive Drawable and override the draw() method. There put the code responsible of drawing the content, e.g. OpenGL calls:

class MyDrawable : public glfwm::Drawable {
    public:
    void draw(const glfwm::WindowID id) override
    {
        // draw the content on the screen
    }
};

Then create some Window and bind the handler and the drawable to it:

std::shared_ptr<MyHandler> myHandler = std::make_shared<MyHandler>();
std::shared_ptr<MyDrawable> myDrawable = std::make_shared<MyDrawable>();
glfwm::WindowPointer mainWin = glfwm::WindowManager::createWindow(800, 600, std::string(), myHandler->getHandledEventTypes());
mainWin->bindEventHandler(myHandler, 0);    // 0 is the rank among all event handlers bound
mainWin->bindDrawable(myDrawable, 0);       // 0 is the rank among all drawables bound

Possibly create other windows and group them. Groups are useful for concurrent management (i.e. multi-threaded windows) or even just for sending notifications to all the windows in the same group. Notifications can be used to make several windows react to a single event. To create a group and attach windows:

glfwm::WindowGroupPointer grp = glfwm::WindowGroup::newGroup();
grp->attachWindow(mainWin->getID());
grp->runLoopConcurrently();     // this is available only if compiled with WITH_MULTITHREADING=ON

Finally, start the main loop, which ends when all the windows are closed, and release the library resources:

glfwm::WindowManager::mainLoop();
glfwm::WindowManager::terminate();

See the examples for more details.

It has been tested on macOS's: 10.9 - 10.10 - 10.11 - 10.12 - 10.13 - 10.14 - 14.3

License

This software is subject to the zlib/libpng License.